A method selects the setting of a first operating parameter of a ventilation system that includes devices for feeding breathing air to and removing from a patient (7), a display device (13) with a screen (15) and a computer (11). The method includes presetting a first target value range for a first ventilation parameter, calculating permissible first operating parameter values by the computer (11) for the first operating parameter, so that the first ventilation parameter value is within the target value range if a permissible first operating parameter value is set calculating values of a preset cost function, which is a function of at least one operating parameter, by the computer (11) selecting a first operating parameter value by the computer (11), at which the value of the cost function has an optimum and outputting the selected first operating parameter value on the screen (15) of the display device (13).
